PACK BATTERY CHARGING METHOD, PACK BATTERY, AND POWER SOURCE DEVICE

A pack battery charging method is a charging method for connecting pack battery to charger and charging pack battery at a constant voltage and a constant current. Pack battery detects a degree of deterioration of battery and a supply voltage at which charger charges pack battery, and specifies a charging termination current from both the supply voltage of charger and the degree of deterioration of battery to perform charging.